Because the picture of the "gayroller 2000" is very obvious satire from the known-satire comic The Oatmeal, originally posted to satirise conservatives' baseless fears of "the gay agenda". Seeing a pattern?
On the other hand, there a pattern of hostility, hatred, and violence from conservatives towards LGBT people. This pattern is both historical and contemporary, and currently it is absurdly common for LGBT people to be called "groomers" and be accused of being dangerous to children.
Gay people obviously do not want to run over straight people with a steamroller. On the other hand, the people posting wood chipper memes... Some of them would, and have, followed through.
18+ [Content Warning: Transphobia] From the very same people who tell us to "boycott Wayland"
Transphobic comments...